What happened to Earth's first atmosphere?
A) It remains part of its present atmosphere, although it has been mixed with nitrogen and oxygen.
B) It was blown away by an early flare-up of the evolving Sun.
C) Its molecules were moving too rapidly to be held by Earth's gravitational pull.
D) It dissolved in the oceans as soon as these were formed.

Question

Quizplus · Accepted Answer

Earth's first atmosphere, composed mainly of hydrogen and helium, was lost because these light gases were moving too rapidly to be retained by Earth's gravity.

What Happened to Earth's First Atmosphere